A goods train, 158 metres long, leaves Delhi at 6 a.m. and travels at an average speed of 32 km/hr. A mail train, 130 metres long, leaves Delhi at 12 noon and follows the goods train travelling at an average speed of 80 km/hr. At what time and at what distance from Delhi will the mail train completely cross the goods train?

By 12 noon, the goods train has a 6 hour head start, travelling 6 hours at 32 km/hr to cover 192 km. The relative speed of the mail train catching up from behind is 80 km/hr minus 32 km/hr, resulting in 48 km/hr. To close the 192 km gap, the mail train takes 192 divided by 48 hours, which equals 4 hours. In these 4 hours, the mail train travels 4 times 80 km from Delhi, totaling 320 km, and the exact crossing time accounting for train lengths is 4 hrs and 1.8 min. This results in a distance of 320 km at approximately 4:02 PM, which is not listed among the specific options. The correct choice is None of these.

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